XRF measurement apparatus for detecting contaminations on the bevel of a wafer

Abstract

An XRF (XRF=x-ray fluorescence) measurement apparatus (1) has an x-ray source (2) for generating x-rays (4), x-ray optics (3) for directing x-rays (4) from the x-ray source (2) to a sample (5) and an EDS (EDS=energy dispersive spectroscopy) detector (7) for detecting fluorescent x-rays (14) from the sample (5). The apparatus is characterized in that the sample (5) is a wafer (6), in particular a Si wafer, wherein the x-ray optics (3) is positioned to direct the x-rays (4) onto the bevel (12) of the wafer (6). The x-ray source (2) plus the x-ray optics (3) has a brilliance of at least 5*107 counts / sec mm2, preferably at least 1*108counts / sec mm2. The apparatus allows an improved contamination control of wafers, in particular silicon wafers.

Description

[0001]This application claims Paris convention priority from EP 13 153 344.0 filed Jan. 30, 2013, the entire disclosure of which is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]The invention relates to an XRF (XRF=x-ray fluorescence) measurement apparatus, comprising[0003]an x-ray source for generating x-rays,[0004]x-ray optics for directing x-rays from the x-ray source to a sample,[0005]the sample,[0006]and an EDS (EDS=energy dispersive spectroscopy) detector for detecting fluorescent x-rays from the sample.[0007]Such an XRF measurement apparatus is known from U.S. Pat. No. 5,778,039 A.[0008]Wafers, in particular silicon wafers, are a basic component in the production of semiconductor electronics. These semiconductor electronics are based on pn-transitions, in particular in diodes and transistors. Semiconductor material of p-type and n-type is produced by carefully controlling the chemical composition of a basic material (such as silicon). More specifically, do...

AI Technical Summary

Benefits of technology

The invention proposes to use XRF (X-ray fluorescence) to detect contaminations on the bevel of a wafer, like silicon, by directing X-rays onto the bevel. By analyzing the XRF signals, contaminations can be identified quickly and non-destructively. The use of a high-brillance X-ray source ensures sufficient signal levels for reliable detection. The method is non-destructive and not likely to introduce new contaminations. An inventive apparatus for implementing this method is also described.

Problems solved by technology

This geometry results in larger signal levels from contaminations, as compared to incident primary beams closer to a perpendicular orientation.

Images